Inductor-magneto alternator.



I J. LE PONTOIS.

INDUGTOR MAGNETO ALTERNATOR.

APPLICATION FILED JULY 11I 1908. 1 098 452, Patented June 2, 1914.

3 SHEETS-SHEET 1.

lnvenioz? .fliiorneya.

L. J. LE PONTOIS;

INDUGTOR MAGNBTO ALTERNATOR.

APPLICATION FILED JULY 11, 1908.

3 SHEET3-BHEET 2.

L. J. LE PONTQIS.

INDUGTOR MAGNBTO ALTERNATOR. APPLIOATION FILED JULY 11,1908.

1,098,452, Patented June .2, 1914.

3 8EEETSSHEET 3.

LEON J. LE PONTOIS,

OF NEW ROCHELLE, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO H. W.JOHNS.

INDUCTOR-MAGNETO ALTERNATOR.

Specification of Letters Patent.

Patented J une 2, 1914.

Application filed July 11, 1908. Serial No. 443,023.

To all whom it may concern:

Be it known that I, LEON J. Ln Powrors, a citizen of the Republic ofFrance, residing at New Rochelle, in the county of VVestchester andState of New York, have invented certain new and useful Improvements inInductor-Magneto Alternators, of which the following is a full, clear,and ex act specification.

My invention relates to alternating current machines and moreparticularly to an alternator of the magneto inductor type, and althoughespecially well adapted for the production of an ignition spark for gasengines, yet my improvements may be utilized in other forms ofapparatus.

One objection to magneto generators resides in the fact that in order toproduce magneto generators in which the strength of the magnetic fieldwill be maintained for a suitable length of time and in which themagnetic leakage will not be excessive, it is necessary that the lengthof the permanently magnetized portions of the magnetic circuit. becomparatively great. With such magnets and with proper attention todesign, an efiicient magneto and one in which the permanency of themagnetic circuit will be maintained can be produced. In some classes ofwork, however, the comparatively large size of the machine isobjectionable and, of course, involves greater expense in construction.In motor vehicles driven by gas engines, it is particularly importantthat the size of the magneto generator be small.

By my invention I have succeeded in producing a magneto inductorgenerator very small in size and particularly well adapted for use onmotor vehicles having the power supplied by gas engines.

My invention will be understood from the following description andaccompanying drawings, in which Figure 1 is a vertical cross sectionalview of one form of machine embodying my invention; Fig. 2 is alongitudinal cross section thereof; Fig. 3 is a sectional view on theline 3-3 of Fig. 2; Fig. t is an end view of the machine; Fig. 5 is adiagram of electrical connections; Flg. 6 is a wave diagram; Fig. 7 is amodified-diagram of electrical connections; Fig. 8 is a diagram ofelectrical connections of a modified form of my invention; Fig. 9 is anend view of a machine arranged for making the connections described inconnection with Fig. 8; and Flg. 10 is a detailed View of the camarranged to secure the change of connections described in connectionwith Fig. 8.

Referring to the structure of the machine shown in Figs. 1 to 4, thesame comprises pedestals 1., 1 for supporting the machine as a whole andhaving bearings for permitting the angular adjustment of the externalelement of the machine to any fixed position desired for adjusting thetime of maximum current generation. The external field element iscircular in general outline and is built up of laminae 2 of the formshown in Fig. 1. Each lamina of iron or steel comprises permanentlymagnetized hardened portions 3, 3 having integral therewith the softiron polar extensions N, N and S, S as Well as soft iron connectingbridges a, 4. The soft iron polar extensions and connecting bridges maysometimes be otherwise secured to the permanently magnetized portions 3,3 of hardened iron, but I prefer to form all of these parts in anintegral lamina or plate, as indicated in the drawings. Each of theplates 2 may bemagnetized by placing the surfaces of the two opposingcentral portions in close proximity respectively to the north and southpoles of a powerful magnet which will complete its magnetic circuitthrough the portions 3,3 and develop two consequent poles of oppositepolarity in the central opposing portions. The extensions N, N willtherefore assume one polarity, say north, while the extensions S, S ofthe opposite central portion will assume the opposite or south polarity.I have obtained the best results by placing the plates 2 in closeproximity to the magnetizing electromagnet as above referred to whilethe plates are at a high temperature of 715 degrees C. The portions 3, 3which are to be permanently r agnetized are then suddenly cooled andhardened while under the influence of the magnetic field. The centralport-ions comprising the polar extensions and the connecting bridges 4,"l" remain annealed and when the plate is removed from the influence ofthe electromagnet, the central portions are magnetized only by theinductive action of the permanently magnetized portions 3, 3. 3y thusproviding an integral plate which is hardened and pern'ianc-ntlymagnetized in certain portions while having soft iron portions of highpermeability, I obtain magnetic circuits of minimum reluctance, and alsosecure great strength and rigidity in the magnetic structure. It will benoted that the form of the field structure secures a Very compactarrangement, giving small size tothe machine and although thepermanently magnetized portions have magnetic circuits of short lengthand therefore not so well adapted for maintaining their strength andpermanency, yet I proride means for assisting the magnets in maintaininga high field strength and thus C0l1li 3n$tlt0 for the comparativelyshort length of the permanently in agnetized parts.

The plates 1., after being built up to form the field frame, are clampedtogether in any suitable manner as by through bolts 5, and siuported asa whole by end plates 6 which are rotatably mounted in the pedestals l,Wound around the bridge portions 4, 4: are the gmieratiug coils 7, 7. Afew of the huninv at the ends of the field frame have the portions .1:,it removed in order that the generating windings 7. 7 will not extendbeyond the ironportion of the field frame, the inner surface at one endof the cgil 7 being indicated by a dotted line in Fig. 2. Surroundingthe polar extensions N, N is placed an exciting coil 8, and around thepolar extensions S, S is placed a similar exciting coil S. By reason ofthe end portions of the coils T, 7 not extending beyond the iron framethese coils will be inclosed by the coils 8, S 'and thus avoid undueincrease in length of the machine, although of course, this constructionmay be departed from where small size of the machine is not such animportant factor. Between the end plates 6 and the laminae 2 areinserted spacing portions 9 of little greater width than the endportions of the coils 8, 8. Around the field frame is a non-magneticsheathing 10 for protection of the parts. One of the end plates isprovided with an extending part .11 to which an operating rod may beconnected for the purpose of conveniently adjusting the angular positionof the field frame as a whole for advancing or retarding the time ofmaximum current generation. Within the extensions 6 are formed rollerbearings for supporting the shaft 12 of the inductor 13, part of theinductor and shaft 12 being broken away in Fig. 2 for the purpose ofshowing the structiire of the field element to better advantage. Theinductor13 is shown in cross section in Fig. 1, and I prefer to make thedistance between the tips of the poles N and S and between N and Ssomewhat less than the distance between the poles N and N and between Sand S, as indicated in Fig. 1, for the reason hereafter explained.

The inductor or rotor 13 will be driven by the gas engine whose sparkingis to be controlled, and in the'present instance the ratio of the speedswill be 1 to 1, or, in other words, for each revolution of the engine,the inductor 13 will also make one revolution. ()n the shaft 12 ismounted a cam 14 for controlling the production of the spark in theengine cylinders. A roller 15 engages the cam and a spring 16 tends tomaintain the roller 15 in engagement with the cam. The roller is carriedby a lever 17 mounted upon a shaft 18 which is mounted in and extendsthrough a partition 19 secured to the stationary element of the machine,which partition. also protects the make and break contacts from the oilof the-bearings. The shaft 18 carries upon its outer end an extension 20which in turn carries a movable contact 21. and the latter is adapted tomake and break connection with afixed contact 22.

The electrical connections and circuits are shown in Fig. The twogenerating coils 7, 7 are shown connected in parallel with each otherand in series with the two exciting coils 8, S which latter areconnectedi'in parallel with each other. Electrical connection is madefrom terminals of the generating windings to one terminal of a primarywinding 23 of a transformer, the remaining terminal. of winding 23 beingconnected to the exciting coils 8, 8. In parallel with the generatingand exciting coils and with the primary winding 23 is connected a.suitable condenser 24. The make and break device already described isconneeted so that the movable contact '21 is connected to one side ofthe circuit and the fixed contact 22 is connected to the other side ofthe circuit; thus when the terminals 21, 22 are in contact, a shortcircuit is made'between the two sides of the main circuit and in thismanner closes a circuit containing the generating and exciting coils inone loop. as well as short circuiting the terminal of the condenser andprimary winding 23. The secondar winding 3 of the transformer i shownconnected in series with a spark plug 25 of the usual type and it willbe understood that the usual distributer will be connected in thesecondary transformer circuit for controlling the connections to thespark plugs in the different engine cylii'iders. The distributor andvarious spark plug circuits are not illustrated however as theiroperation is well understood.

In order to explain the operation of the machine, we may consider thewave indicated in Fig. (3, and although the electrometive force actuallyproduced will be of irregular form. yet the general form of waveindicated in Fig. 6 will sufhce for the purposes of explanation, thesolid portions of the curve representing positive electromotive forcevalues, and the dotted portions negative values.

When the inductor 13 is in the general position a, a, the magnetic fluxthrough the inductor will be a maximum. The path of the magnetic flux inthis position through the generating windings will be in one circuitfrom pole N' through the inductor to pole S, through the yoke portion 3,then through the bridge connection 4 and coil 7 to pole 1*. In anotherpath the flux will pass from pole N through the inductor to pole S,thence through the bridge connection t and coil 7, and then through theyoke portion 3 to pole N. The magnetic flux through the generatin coilswill then be a maximum and as at t is time the rate of flux change iszero, the electromotive force will be substantially zero as indicatedat'a in Fig. 6. The coils 7, 7 are connected in parallel so that theirelectromotive forces Will act in the same direction in the electriccircuit, although if desired the coils may be connected in series witheach other. As the inductor passes from the position a, a, assumingright hand rotation, the reluctance of the magnetic circuit will beincreased by reason of the inductor passing from under the poles N andS. This increase in reluctance causes decrease of flux through thegenerating coils in the paths previously traced and thereby causesincrease in electromotive force generated, so that when the inductor isin position b, b, the rate of change in flux is a maximum approximatelyand this results in the generation of maximum electromotive force asindicated at b, in Fig. 6. As the rotor approaches position 0, c, therate of change of flux decreases until in position a the flux throughthe generating windings in the opposite direction becomes a maximum andthe rate of change is practically Zero, giving in this position 0practically-no electromotive force, as indicated at c in Fig. 6. Thepaths of the magnetic flux in the position 0, c, of the inductor will beas follows: One path from pole N through the inductor to pole S, thencethrough the yoke 3 passing through the bridge 4, and coil 7 back to poleN, and in another path from pole N through the inductor to pole S,through bridge 4: and coil 7, thence through the yoke 3 to pole N. Asthe inductor passes from position 0, 0, the flux through the generatingwindings will begin to decrease causing eloctromotive force to begenerated therein in the opposite direction and at position (5, clapproximately. the rate of change of flux is a maximum giving maximumelectromotive force in the opposite direction as indicated at (Z of Fig.6. As the inductor approaches position a, a, the magnetic flux increasesin the opposite direction through the generating coils and in positiona, or, approximately the rate of change is zero although the fluxthrough the windings is a maximum giving zero electromotive forceapproximately, as indicated at a in Fig. 6. The path of the magneticflux will then be the same as previously traced when the inductor was inp0 sition a, a, reversed. As the inductor continues its revolutionfrom-the position a, a to positions 6, Z), c, 0, (Z, (Z and back to a,a, the cycle of electromotive force generation will he understood asbeing indicated in positions b, c, d and a, respectively. It willtherefore be seen that in one complete revolution of the inductor, theelectromotive force generated will correspond in a general way to thatindicated in Fig. 6, giving two positive and two negative waves. It willbe understood that the above description of changes is very generalwithout considering the various factors that modify the form of the waveor the action at different positions and is described for the purpose ofindicating in a general way what occurs during one complete revolutionof the inductor.

One important factor which modifies the action above referred to is theinduction of the circuits and such induction will, of course, cause thecurrent which flows to lag behind the induced electromotive force.Consequently, the maximum current strengths will not occur when theinductor is in positions 7), b and (i, (Z, but will occur after theinductor has advanced beyond these positions. As the engine is geared tothe magneto in the ratio of 1 to 1 and as in the present instance anengine requiring two explosions per revolution is contemplated, twosparks should be produced per revolution of the magneto and these ofcourse should occur when the current is a maximum. The form of the camll is such that the contacts 21, 22 will be separated twice perrevolution when the current is a maximum and flowing in say positivedirection and will remain separated until the current has decreased tozero and reversed and decreased to zero agaln. The contacts Wlll be'closed during increase in current to maximum value in a positivedirection. The cam 14. is therefore provided with two diametricallyopposite raised portions 14c, which will operate to raise the roller 15and separatcthe contacts of the breaker during the periods abovementioned and permit the breaker to be closed during the other periods.

The connections of exciting coils 8, 8' are such that when the twopositive waves -for example are generated, the direction of currentthrough the exciting coils will tend to maintain and build up thestrength of the magnetic field. Considering the action more in detail.it will be understood that during the generation of the increasingportion of the positive waves, the direction of current in thegenerating coils 7, 7 will. be such as to also tend to build up andstrengthen the magnetic field. During the decreasing portion of thepositive waves, the current in the generating windings will oppose themagnetic flux in the new paths and therefore tend to demagnetize andweaken the field element. This demagnetizing action of the generatingwindings will be counter-acted 1 by the current in the exciting coilswhich,

of course, continues to maintain the mag netic field strength during thegeneration of the positive waves. During the generation of the negativewaves the increasing negative currents in the generating Windings willtend to maintain the magnetic field but will tend to demagnetize thefield during the decreasing portion of the negative waves. The currentflowing in the exciting coils during the generation of the negativewaves, will, of course, tend to demagnetize the field element, but thedemagnetizing effect will be very much less than the magnetizing effect.In the first place the demagnetizing action of the exciting coils occursat a time when the energy is not being utilized and its effect duringthe generation of negative waves is therefore comparatively unimportantin View of the magnetizing effect which afterward occurs during positivewave generation when the energy is utilized in the spark discharges.Again during the generation of negative Waves, the circuit breaker beingopen, the generating coils, exciting coils and primary winding 23 willbe connected in series with each other, giving maximum impedance in thecircuit, which will of course, tend to cause the negative current tohave less value than the positive current when the circuit breaker isclosed. Also by reason of the space between-the tips of the poles N, S,and between the tips of the poles N, and S being less than the spacebetween the poles N and N and between the poles S and S, there will begreater leakage during the generation of the negative waves which willalso tend to decrease the value thereof com-- pared with the value ofthe positive waves. The effect of the various actions is such as tomaintain the magnetic field strength indefinitely even thoughalternating current waves are passed through the circuit of the excitingcoils and even though the permanently magnetized field element is ofcomparatively small size with short magnetic circuits. Also at the timethe energy is utilized, the generation is such as to give heavy sparkdischarges.

In Fig. 7, another form of connections is illustrated, the condenser 24being connected in series in the circuit instead of in parallel as inFig. 5, and the breaker when closed is adapted to short circuit theconillustrates another modification. The exciting coils 8, 8 instead ofbeing permanently connected in series with the generating coils 7, 7 areadapted to be cut in and out of circuit by the operation of the breaker.The flexible arm 20 of the breaker instead of making one contact as inthe forms pre' viously considered, is adapted to engage the fixedcontact 30 in one position, thereby closing a circuit through thegenerating coils and excitin coils, and in another position is adaptedto engage the contact 31 thereby removing the exciting coils fromcircuitand short circuiting the generating coils; when the circuitbreaker is in open position, the spark will be produced. The form of thecam 32 used in this construction will be as shown in Fig. 10. Therelation of the cam to the roller 15 controlled thereby, will be suchthat during the period of increasing current in say the positivedirection, the generating windings will be closed 011 themselves, andwhen the current attains or approaches a maximum in this direction, thebreaker will be opened by the cam for causing the spark discharge.

hen the negative current is afterward generated, the cam will cause thebreaker to be closed through the generating coils and exciting coils,the connection of the exciting coils being such that the negativecurrent which fiows will tend to magnetize and strengthen the fieldelement. When the current again changes direction and begins to increasein a positive direction, the breaker will cause the exciting coils to bedisconnected from circuit and then close the generating coils onthemselves, after which the breaker will be opened for causing the sparkdischarge, and finally the breaker will close the circuit through theexciting coils again when the direction of current is reversed. Thiswill complete the cycle per revolution of the machine and the samesequence 0 connections will afterward be repeated. Referring to the camshown in Fig. 10, when the roller bears on line 33 the flexible arm 20is forced in such direct-ion as to'cause engagement with contact 31closing the circuit of the generating windings on themselves, and thiscondition of connections will continue during the period of increasingpositive current. When the cam is turned so that the roller bears online 84, the circuit through contact 31 will be broken, causing thespark, discharge, and the breaker will remain open until the rollerbears on line 35 when the circuit through contact 30 will be closed.This, as above referred to, will closethe circuit of the generatingcoils through the exciting'coils' and this condition will continueduringthe flow of the negative current approximately. When the, rollerbears online 33', the conditions will be the same as when the roller wason line 33 and it. will be-noted that there is an abrupt change on thecam above line 33 so as to cause the arm 20 to be rapidly thrown fromcontact 30 to contact 31. As the roller passes over the remaining halfof the cam,

the sequence of connections obtained will be the-same as above referredto.

It will be understood that various other modifications-may be devisedand various changes made in design without departing from the scope ofmy invention.

Having thus described my invention, I declare that what I claim as newand desire to secure by Letters Patent, is,-

1. In an inductor alternator, a generating winding embracinga portion ofthe magnetic circuit which is subjected to the maximum change inmagnetic flux, an exciting winding supplied with alternating currentfrom the generating winding and embracing a portion of the field elementwhich is subjected to less change in magnetic flux,

and circuit changing means for causing the current wave through saidexciting winding in one direction to be more efiective for exciting thefield element than the current wave in the opposite direction.

2. In an alternating current generator, a generating winding embracing aportion of the magnetic circuit which is subjected to the maximum changein magnetic flux, an exciting winding supplied with alternating currentderived from said generating winding for strengthening the field elementand embracing a portion of the field element which is'subjected to lesschange in ma netic flux, and means connecting said win ings in serieswith each other.

3. The combination of a permanently. magnetized field element, aninductor, a

generating winding on the field element, and an exciting winding on thefield element supplied withalternating. current from saidgeneratingwinding.

4. A dynamo electric generator'for supplying energy to a sparkingdevice, comprising a plurality of generating windings on the fieldelement, a plurality of ex-, citing field windings on the field elementsupplied with alternating current from said generating windings, andmeans for varying the flux through said generating windings.

5. In an inductor alternator, a generating winding, and an excitingwinding for the field element supplied with alternating current from thegenerating winding, the field element having unequally spaced partsprojecting toward the rotor for causing the current wave in onedirection to be more effective for exciting the field element than thecurrent wave in'the opposite direction.

6. A generator having a stationaryanda rotating element, an alternatingcurrent generating winding onthe field element embracing a ortion of themagnetic circuit which is sub ected to-the maximum change in magneticflux, and a field winding on the field element embracing a portion ofthe magnetic circuit which is subjected to less change in magnetic flux,said generating winding and said field winding being connected to eachother to cause said field winding to be supplied from said generatingwinding with current of the same character as generated in saidgenerating winding.

7. The combination of a generator'havingan alternating currentgenerating winding for supplying a sparking discharge current when thealternating current therein is a maximum value in one direction, afieldwinding, and circuit'changin means and connections for causing said eldwinding to be supplied with current from said generating' windin whenthe current flow-s in said-one directlon and for causing a lessercurrent. to be supplied to said field winding when the current flows inthe opposite direction, said circuit changing means being controlled bysaid generator and forming a' unitary structure therewith.

8. The combination of a generator having a stationary element,-arrotating element, a plurality of alternating currentgenerating windingsrality of exciting windings located onthe same element as saidgenerating-winding and supplied with' current from said generatingwindings, :and circuit changing means for causing the current assingthrough said exciting windings to ave a higher value when the currentflows in the direction in whichv magnetization of said. same element iseffected.

9. The combination of a generator having a. stationary element and arotating element, an alternating current generating winding forsupplying a sparking discharge current, an exciting winding suppliedwith current from said generating w1nding,both of said windings beinglocated on the stationary element, andthe field element havingunequallyspaced parts projecting toward-the rotating element for causinthe current wave energized in one direction to efiect a greaterexcitation of the field element than on one of said elements, aplusions, anda rotor for reversing the mag,

netic fiux through said generating windings. 12. The combination ofafield element built up of a plurality of plates, eachof said platescomprising a permanently mag-p netized hardened portionand soft ironportions integral therewith, a generating 'winding, and an excitingwinding for increasing;

I the strength of said field element.

13. The combination of .a field element comprising a plurality ofpermanently magnetized portions and a plurality of soft iron polarextensions, a generating-winding on said fieldelement, and an excitingwinding for said field element supplied with current from saidgenerating winding,and a rotor;

for reversing the magneticnflux through said generating winding.

14. In a magneto generator of the inductor type, the combinationyof astationary frame comprising an integral member, said member having twopermanently magnetized portions of hardened iron and portions of softiron connecting poles. of like polarity and integral with-saidmagnetized portions,

windings on said soft iron portions, an exciting winding for increasingthe magnetic strength of said frame supplied with energy from said firstnamed windings, and a rotor for controlling the paths ofthe magneticflux.-

15. In a magneto generator of the inductor type, the combination of apermanently magnetized field frame having a plurality of soft iron polarprojections, a generatingv winding on said frame, an exciting windingfor strengthening the magnetic field, supplied with current fromsaidgenerating winding, andv a rotortfor controlling the paths of themagnetic fiux..

16. In a magneto generator, thecombi-nation of an element comprising apermanently magnetized portion of hardened iron and 7 soft iron polarportions, a secondv element for controlling the paths of the mag.- neticflux, a generating winding on one .of said elements, and an excitingwindingon saidfirst named element supplied with cur rent from saidgenerating winding,.and of the. same character as flows insaidgenerating winding, for increasingthe magnetism of said element.

17. In a magneto generator of'the inductor type, the combination-of aframe having permanently magnetized portions. of bar dened iron,portions of soft -1IOI1' connecting poles of like polarityand having,polar extensions, generating windings on said soft iron portions, arotor vfor controlling the paths of the magnetic flux, and an excitingwinding inclosing said polar extensions of 7 said element supplied withcurrent from said first named winding;

18. In an alternating current generator, the combination of apermanently magnete ized field element, a generating winding, an.exciting Winding for strengthening thev magnetism of the field element,said exciting winding being electrically connected with and suppliedwithpcurrent from said generating winding, and circuit controlling meansfor causing the current passing through sald excltmg winding to have ahigher value when the current: flows in one direction than when thecurrent flows in the opposite direction.

19. The combination of a field-element having. apolar extensionand-comprising two permanently magnetized 3 ortions having soft ironportions connecting like poles of said permanently magnetized portions,generating windings on said connecting portions, a rotor for reversingthe magnetic flux through said-windings, and an exciting coil suppliedwithcurrent' from at least one of said windings inclosingsaidpolarextent sion of said element.

In testlmony whereof I afiix my-signa-' ture, in presence oftwowitnesses.

LEON J. LE PONTOIS. Witnesses:

BENJAMIN Hum),

L. K. SAGE.

